{"id":15070,"date":"2020-03-12T10:57:31","date_gmt":"2020-03-12T03:57:31","guid":{"rendered":"https:\/\/kiencang.net\/?p=15070"},"modified":"2020-03-12T10:57:31","modified_gmt":"2020-03-12T03:57:31","slug":"preconnect-dns-prefetch","status":"publish","type":"post","link":"https:\/\/kiencang.net\/preconnect-dns-prefetch\/","title":{"rendered":"Th\u00e0nh l\u1eadp c\u00e1c k\u1ebft n\u1ed1i m\u1ea1ng s\u1edbm (preconnect) \u0111\u1ec3 c\u1ea3i thi\u1ec7n t\u1ed1c \u0111\u1ed9 website"},"content":{"rendered":"\n<p>Trong b\u00e0i vi\u1ebft n\u00e0y ch\u00fang ta s\u1ebd c\u00f9ng h\u1ecdc c\u00e1ch s\u1eed d\u1ee5ng c\u00e1c ki\u1ec3u g\u1ee3i \u00fd t\u00e0i nguy\u00ean <em>rel=preconnect<\/em> v\u00e0 <em>rel=dns-prefetch<\/em>.<\/p>\n\n\n<p>Tr\u01b0\u1edbc khi tr\u00ecnh duy\u1ec7t c\u00f3 th\u1ec3 y\u00eau c\u1ea7u m\u1ed9t t\u00e0i nguy\u00ean t\u1eeb m\u00e1y ch\u1ee7, n\u00f3 ph\u1ea3i th\u00e0nh l\u1eadp k\u1ebft n\u1ed1i. Th\u00e0nh l\u1eadp m\u1ed9t k\u1ebft n\u1ed1i b\u1ea3o m\u1eadt (secure connection) li\u00ean quan \u0111\u1ebfn ba b\u01b0\u1edbc:<\/p>\n\n\n<ul><li>T\u00ecm ki\u1ebfm t\u00ean mi\u1ec1n v\u00e0 ph\u00e2n gi\u1ea3i n\u00f3 th\u00e0nh \u0111\u1ecba ch\u1ec9 IP;<\/li><li>Thi\u1ebft l\u1eadp k\u1ebft n\u1ed1i t\u1edbi m\u00e1y ch\u1ee7;<\/li><li>M\u00e3 h\u00f3a k\u1ebft n\u1ed1i \u0111\u00f3 \u0111\u1ec3 n\u00f3 b\u1ea3o m\u1eadt.<\/li><\/ul>\n\n\n<p>Trong t\u1eebng b\u01b0\u1edbc tr\u00ean tr\u00ecnh duy\u1ec7t g\u1eedi m\u1ed9t ph\u1ea7n d\u1eef li\u1ec7u t\u1edbi m\u00e1y ch\u1ee7, v\u00e0 m\u00e1y ch\u1ee7 g\u1eedi l\u1ea1i m\u1ed9t ph\u1ea3n h\u1ed3i. H\u00e0nh tr\u00ecnh n\u00e0y, t\u1eeb m\u00e1y ch\u1ee7 g\u1ed1c \u0111\u1ebfn \u0111\u1ecba ch\u1ec9 c\u1ea7n \u0111\u1ebfn v\u00e0 quay ng\u01b0\u1ee3c tr\u1edf l\u1ea1i, \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 <a href=\"https:\/\/developer.mozilla.org\/en-US\/docs\/Glossary\/Round_Trip_Time_(RTT)\" target=\"_blank\" rel=\"noreferrer noopener\">kh\u1ee9 h\u1ed3i (round trip)<\/a>.<\/p>\n\n\n<p>Ph\u1ee5 thu\u1ed9c v\u00e0o t\u00ecnh tr\u1ea1ng k\u1ebft n\u1ed1i, m\u1ed9t v\u00f2ng kh\u1ee9 h\u1ed3i c\u00f3 th\u1ec3 c\u1ea7n m\u1ed9t l\u01b0\u1ee3ng th\u1eddi gian \u0111\u00e1ng k\u1ec3. Qu\u00e1 tr\u00ecnh thi\u1ebft l\u1eadp k\u1ebft n\u1ed1i c\u00f3 th\u1ec3 li\u00ean quan \u0111\u1ebfn ba v\u00f2ng kh\u1ee9 h\u1ed3i-v\u00e0 nhi\u1ec1u h\u01a1n n\u1eefa trong c\u00e1c tr\u01b0\u1eddng h\u1ee3p ch\u01b0a \u0111\u01b0\u1ee3c t\u1ed1i \u01b0u.<\/p>\n\n\n<p>N\u1ebfu b\u1ea1n th\u1ef1c hi\u1ec7n ki\u1ec3u k\u1ebft n\u1ed1i &#8216;\u0111i t\u1eaft \u0111\u00f3n \u0111\u1ea7u&#8217; cho t\u1ea5t c\u1ea3, b\u1ea1n s\u1ebd gi\u00fap c\u00e1c \u1ee9ng d\u1ee5ng nhanh h\u01a1n nhi\u1ec1u. B\u00e0i vi\u1ebft n\u00e0y gi\u1ea3i th\u00edch c\u00e1ch \u0111\u1ea1t \u0111\u01b0\u1ee3c \u0111i\u1ec1u \u0111\u00f3 v\u1edbi hai g\u1ee3i \u00fd t\u00e0i nguy\u00ean: <code>&lt;link rel=preconnect><\/code> v\u00e0 <code>&lt;link rel=dns-prefetch><\/code>.<\/p>\n\n\n<hr class=\"wp-block-separator\"\/>\n\n\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_60 counter-hierarchy ez-toc-counter ez-toc-light-blue ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title \" >M\u1ee5c l\u1ee5c<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\" role=\"button\"><label for=\"item-6577d65c237cc\" ><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/label><input aria-label=\"Toggle\" aria-label=\"item-6577d65c237cc\"  type=\"checkbox\" id=\"item-6577d65c237cc\"><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/kiencang.net\/preconnect-dns-prefetch\/#Thanh_lap_ket_noi_som_voi_relpreconnect\" title=\"Th\u00e0nh l\u1eadp k\u1ebft n\u1ed1i s\u1edbm v\u1edbi rel=preconnect\">Th\u00e0nh l\u1eadp k\u1ebft n\u1ed1i s\u1edbm v\u1edbi rel=preconnect<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/kiencang.net\/preconnect-dns-prefetch\/#Cac_truong_hop_su_dung_relpreconnect\" title=\"C\u00e1c tr\u01b0\u1eddng h\u1ee3p s\u1eed d\u1ee5ng rel=preconnect\">C\u00e1c tr\u01b0\u1eddng h\u1ee3p s\u1eed d\u1ee5ng rel=preconnect<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/kiencang.net\/preconnect-dns-prefetch\/#Cach_trien_khai_relpreconnect\" title=\"C\u00e1ch tri\u1ec3n khai rel=preconnect\">C\u00e1ch tri\u1ec3n khai rel=preconnect<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/kiencang.net\/preconnect-dns-prefetch\/#Phan_giai_ten_mien_som_voi_reldns-prefetch\" title=\"Ph\u00e2n gi\u1ea3i t\u00ean mi\u1ec1n s\u1edbm v\u1edbi rel=dns-prefetch\">Ph\u00e2n gi\u1ea3i t\u00ean mi\u1ec1n s\u1edbm v\u1edbi rel=dns-prefetch<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/kiencang.net\/preconnect-dns-prefetch\/#Ket_luan\" title=\"K\u1ebft lu\u1eadn\">K\u1ebft lu\u1eadn<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/kiencang.net\/preconnect-dns-prefetch\/#Bonus_cho_nguoi_dung_WordPress\" title=\"Bonus cho ng\u01b0\u1eddi d\u00f9ng WordPress\">Bonus cho ng\u01b0\u1eddi d\u00f9ng WordPress<\/a><\/li><\/ul><\/nav><\/div>\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Thanh_lap_ket_noi_som_voi_relpreconnect\"><\/span>Th\u00e0nh l\u1eadp k\u1ebft n\u1ed1i s\u1edbm v\u1edbi rel=preconnect<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n<p>C\u00e1c tr\u00ecnh duy\u1ec7t hi\u1ec7n \u0111\u1ea1i c\u1ed1 g\u1eafng h\u1ebft s\u1ee9c \u0111\u1ec3 bi\u1ebft c\u00e1c k\u1ebft n\u1ed1i n\u00e0o s\u1ebd c\u1ea7n, nh\u01b0ng ch\u00fang kh\u00f4ng th\u1ec3 n\u00e0o d\u1ef1 \u0111o\u00e1n ch\u00ednh x\u00e1c t\u1ea5t c\u1ea3 \u0111\u01b0\u1ee3c. Tin t\u1ed1t l\u00e0 b\u1ea1n c\u00f3 th\u1ec3 cung c\u1ea5p cho ch\u00fang g\u1ee3i \u00fd t\u00e0i nguy\u00ean (resource hint).<\/p>\n\n\n<p>Th\u00eam <em>rel=preconnect<\/em> v\u00e0o th\u1ebb <em>&lt;link&gt;<\/em> \u0111\u1ec3 th\u00f4ng b\u00e1o v\u1edbi tr\u00ecnh duy\u1ec7t r\u1eb1ng trang c\u1ee7a b\u1ea1n c\u00f3 \u00fd \u0111\u1ecbnh th\u00e0nh l\u1eadp k\u1ebft n\u1ed1i t\u1edbi t\u00ean mi\u1ec1n kh\u00e1c, v\u00e0 b\u1ea1n mu\u1ed1n qu\u00e1 tr\u00ecnh n\u00e0y b\u1eaft \u0111\u1ea7u c\u00e0ng s\u1edbm c\u00e0ng t\u1ed1t. C\u00e1c t\u00e0i nguy\u00ean s\u1ebd \u0111\u01b0\u1ee3c t\u1ea3i nhanh h\u01a1n b\u1edfi v\u00ec qu\u00e1 tr\u00ecnh thi\u1ebft l\u1eadp \u0111\u00e3 \u0111\u01b0\u1ee3c ho\u00e0n th\u00e0nh tr\u01b0\u1edbc th\u1eddi \u0111i\u1ec3m tr\u00ecnh duy\u1ec7t y\u00eau c\u1ea7u ch\u00fang.<\/p>\n\n\n<p>C\u00e1c g\u1ee3i \u00fd t\u00e0i nguy\u00ean (resource hints) c\u00f3 t\u00ean nh\u01b0 v\u1eady b\u1edfi v\u00ec ch\u00fang <em>kh\u00f4ng ph\u1ea3i l\u00e0 c\u00e1c h\u01b0\u1edbng d\u1eabn b\u1eaft bu\u1ed9c<\/em>. Ch\u00fang cung c\u1ea5p th\u00f4ng tin v\u1ec1 c\u00e1i m\u00e0 b\u1ea1n mu\u1ed1n x\u1ea3y ra, nh\u01b0ng \u0111i\u1ec1u n\u00e0y cu\u1ed1i c\u00f9ng c\u00f3 x\u1ea3y ra hay kh\u00f4ng ho\u00e0n to\u00e0n ph\u1ee5 thu\u1ed9c v\u00e0o tr\u00ecnh duy\u1ec7t c\u00f3 quy\u1ebft \u0111\u1ecbnh th\u1ef1c thi ch\u00fang kh\u00f4ng. C\u00e0i \u0111\u1eb7t v\u00e0 gi\u1eef k\u1ebft n\u1ed1i m\u1edf t\u1ed1n nhi\u1ec1u c\u00f4ng s\u1ee9c, v\u00ec th\u1ebf tr\u00ecnh duy\u1ec7t c\u00f3 th\u1ec3 ch\u1ecdn b\u1ecf qua c\u00e1c g\u1ee3i \u00fd t\u00e0i nguy\u00ean ho\u1eb7c th\u1ef1c thi ch\u00fang m\u1ed9t ph\u1ea7n ph\u1ee5 thu\u1ed9c v\u00e0o t\u00ecnh hu\u1ed1ng c\u1ee5 th\u1ec3.<\/p>\n\n\n<p>Th\u00f4ng b\u00e1o v\u1edbi tr\u00ecnh duy\u1ec7t \u00fd \u0111\u1ecbnh c\u1ee7a b\u1ea1n b\u1eb1ng c\u00e1ch \u0111\u01a1n gi\u1ea3n th\u00eam m\u1ed9t th\u1ebb &lt;link&gt; v\u00e0o trang:<\/p>\n\n\n<pre class=\"wp-block-code\"><code>&lt;link rel=\"preconnect\" href=\"https:\/\/example.com\"&gt;<\/code><\/pre>\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><img decoding=\"async\" src=\"https:\/\/kiencang.net\/wp-content\/uploads\/2020\/03\/preconnect-1024x690-3.png\" alt=\"s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa c\u00f3 preconnect v\u00e0 kh\u00f4ng c\u00f3 preconnect\" class=\"wp-image-15073\"\/><figcaption>Nh\u1edd vi\u1ec7c th\u1ef1c hi\u1ec7n k\u1ebft n\u1ed1i song song (h\u00ecnh b\u00ean d\u01b0\u1edbi), th\u1eddi gian t\u1ea3i trang \u0111\u00e3 \u0111\u01b0\u1ee3c gi\u1ea3m xu\u1ed1ng so v\u1edbi th\u00f4ng th\u01b0\u1eddng (h\u00ecnh b\u00ean tr\u00ean)<\/figcaption><\/figure><\/div>\n\n\n<p>B\u1ea1n c\u00f3 th\u1ec3 gi\u1ea3m th\u1eddi gian t\u1ea3i trang t\u1eeb 100-500ms b\u1eb1ng c\u00e1ch th\u1ef1c hi\u1ec7n c\u00e1c k\u1ebft n\u1ed1i s\u1edbm t\u1edbi <a href=\"https:\/\/kiencang.net\/tai-nguyen-ben-thu-ba-wordpress\/\" target=\"_blank\" rel=\"noreferrer noopener\">m\u00e1y ch\u1ee7 g\u1ed1c quan tr\u1ecdng c\u1ee7a b\u00ean th\u1ee9 ba<\/a> (third-party). Con s\u1ed1 tr\u00ean c\u00f3 v\u1ebb nh\u1ecf, nh\u01b0ng ch\u00fang c\u00f3 th\u1ec3 t\u1ea1o ra s\u1ef1 kh\u00e1c bi\u1ec7t trong nh\u1eadn th\u1ee9c c\u1ee7a ng\u01b0\u1eddi d\u00f9ng v\u1ec1 hi\u1ec7u su\u1ea5t, t\u1ed1c \u0111\u1ed9 trang. V\u00ed d\u1ee5 trang chrome.com c\u1ea3i thi\u1ec7n \u0111\u01b0\u1ee3c <a href=\"https:\/\/kiencang.net\/time-to-interactive-la-gi\/\" target=\"_blank\" rel=\"noreferrer noopener\">Time To Interactive<\/a> g\u1ea7n m\u1ed9t gi\u00e2y nh\u1edd vi\u1ec7c th\u1ef1c hi\u1ec7n k\u1ebft n\u1ed1i s\u1edbm t\u1edbi m\u00e1y ch\u1ee7 g\u1ed1c quan tr\u1ecdng.<\/p>\n\n\n<hr class=\"wp-block-separator\"\/>\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Cac_truong_hop_su_dung_relpreconnect\"><\/span>C\u00e1c tr\u01b0\u1eddng h\u1ee3p s\u1eed d\u1ee5ng rel=preconnect<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n<h3 class=\"wp-block-heading\">Bi\u1ebft ch\u00fang \u0111\u1ebfn t\u1eeb <em>\u0111\u00e2u<\/em>, nh\u01b0ng kh\u00f4ng bi\u1ebft ph\u1ea3i t\u00ecm n\u1ea1p <em>c\u00e1i g\u00ec<\/em><\/h3>\n\n\n<p>V\u00ec ph\u1ee5 thu\u1ed9c v\u00e0o c\u00e1c phi\u00ean b\u1ea3n, \u0111\u00f4i khi b\u1ea1n g\u1eb7p ph\u1ea3i t\u00ecnh hu\u1ed1ng m\u00e0 b\u1ea3n th\u00e2n bi\u1ebft c\u00e1c y\u00eau c\u1ea7u t\u00e0i nguy\u00ean \u0111\u1ebfn t\u1eeb CDN c\u1ee5 th\u1ec3, nh\u01b0ng kh\u00f4ng bi\u1ebft ch\u00ednh x\u00e1c \u0111\u01b0\u1eddng d\u1eabn c\u1ee7a n\u00f3.<\/p>\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"https:\/\/kiencang.net\/wp-content\/uploads\/2020\/03\/vi-du-phien-ban-url.png\" alt=\"V\u00ed d\u1ee5 v\u1ec1 phi\u00ean b\u1ea3n URL\" class=\"wp-image-15084\"\/><figcaption>V\u00ed d\u1ee5 v\u1ec1 phi\u00ean b\u1ea3n URL<\/figcaption><\/figure>\n\n\n<p>Tr\u01b0\u1eddng h\u1ee3p ph\u1ed5 bi\u1ebfn kh\u00e1c l\u00e0 t\u1ea3i \u1ea3nh t\u1eeb <a href=\"https:\/\/kiencang.net\/cdn-toi-uu-anh\/\" target=\"_blank\" rel=\"noreferrer noopener\">CDN \u1ea3nh<\/a>, khi m\u00e0 \u0111\u01b0\u1eddng d\u1eabn ch\u00ednh x\u00e1c c\u1ee7a \u1ea3nh ph\u1ee5 thu\u1ed9c v\u00e0o truy v\u1ea5n media ho\u1eb7c c\u00e1c ki\u1ec3m tra ch\u1ee9c n\u0103ng runtime tr\u00ean tr\u00ecnh duy\u1ec7t ng\u01b0\u1eddi d\u00f9ng.<\/p>\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"https:\/\/kiencang.net\/wp-content\/uploads\/2020\/03\/image-cdn-url-1024x66.png\" alt=\"M\u1ed9t v\u00ed d\u1ee5 v\u1ec1 URL CDN cho \u1ea3nh\" class=\"wp-image-15085\"\/><figcaption>M\u1ed9t v\u00ed d\u1ee5 v\u1ec1 URL CDN cho \u1ea3nh, trong \u0111\u01b0\u1eddng d\u1eabn ngo\u00e0i th\u00f4ng tin th\u00f4ng th\u01b0\u1eddng n\u00f3 c\u00f2n c\u00f3 th\u00eam th\u00f4ng tin v\u1ec1 key, ch\u1ea5t l\u01b0\u1ee3ng, k\u00edch c\u1ee1<\/figcaption><\/figure>\n\n\n<p>Trong nh\u1eefng t\u00ecnh hu\u1ed1ng nh\u01b0 v\u1eady, n\u1ebfu t\u00e0i nguy\u00ean b\u1ea1n mu\u1ed1n t\u00ecm n\u1ea1p (fetching) l\u00e0 quan tr\u1ecdng, b\u1ea1n mu\u1ed1n ti\u1ebft ki\u1ec7m c\u00e0ng nhi\u1ec1u th\u1eddi gian c\u00e0ng t\u1ed1t b\u1eb1ng c\u00e1ch k\u1ebft n\u1ed1i tr\u01b0\u1edbc v\u1edbi m\u00e1y ch\u1ee7. Tr\u00ecnh duy\u1ec7t kh\u00f4ng t\u1ea3i file cho \u0111\u1ebfn khi trang c\u1ee7a b\u1ea1n y\u00eau c\u1ea7u n\u00f3, nh\u01b0ng \u00edt nh\u1ea5t n\u00f3 c\u00f3 th\u1ec3 x\u1eed l\u00fd tr\u01b0\u1edbc \u0111\u01b0\u1ee3c nhi\u1ec7m v\u1ee5 k\u1ebft n\u1ed1i, ti\u1ebft ki\u1ec7m cho ng\u01b0\u1eddi d\u00f9ng kh\u00f4ng ph\u1ea3i \u0111\u1ee3i v\u00e0i v\u00f2ng kh\u1ee9 h\u1ed3i.<\/p>\n\n\n<h3 class=\"wp-block-heading\">Streaming media (ph\u00e1t video, nh\u1ea1c, v\u00e2n v\u00e2n t\u1eeb b\u00ean th\u1ee9 ba)<\/h3>\n\n\n<p>M\u1ed9t v\u00ed d\u1ee5 kh\u00e1c khi b\u1ea1n mu\u1ed1n ti\u1ebft ki\u1ec7m th\u1eddi gian trong pha k\u1ebft n\u1ed1i, nh\u01b0ng kh\u00f4ng nh\u1ea5t thi\u1ebft ph\u1ea3i nh\u1eadn n\u1ed9i dung ngay l\u1eadp t\u1ee9c, l\u00e0 khi b\u1ea1n ph\u00e1t media (nh\u1ea1c, video, v\u00e2n v\u00e2n) t\u1eeb m\u1ed9t m\u00e1y ch\u1ee7 g\u1ed1c kh\u00e1c.<\/p>\n\n\n<p>Ph\u1ee5 thu\u1ed9c v\u00e0o c\u00e1ch trang c\u1ee7a b\u1ea1n x\u1eed l\u00fd n\u1ed9i dung stream, b\u1ea1n c\u00f3 th\u1ec3 mu\u1ed1n \u0111\u1ee3i cho \u0111\u1ebfn khi m\u00e3 c\u1ee7a b\u1ea1n \u0111\u01b0\u1ee3c t\u1ea3i xong v\u00e0 s\u1eb5n s\u00e0ng x\u1eed l\u00fd stream. K\u1ebft n\u1ed1i tr\u01b0\u1edbc gi\u00fap b\u1ea1n c\u1eaft th\u1eddi gian ch\u1edd \u0111\u1ee3i cho m\u1ed9t v\u00f2ng kh\u1ee9 h\u1ed3i m\u1ed9t khi b\u1ea1n \u0111\u00e3 s\u1eb5n s\u00e0ng b\u1eaft \u0111\u1ea7u t\u00ecm n\u1ea1p.<\/p>\n\n\n<hr class=\"wp-block-separator\"\/>\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Cach_trien_khai_relpreconnect\"><\/span>C\u00e1ch tri\u1ec3n khai rel=preconnect<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n<p>\u0110\u1ec3 b\u1eaft \u0111\u1ea7u s\u1eed d\u1ee5ng preconnect, b\u1ea1n th\u00eam th\u1ebb <em>&lt;link&gt;<\/em> v\u00e0o ph\u1ea7n <em>&lt;head&gt;<\/em> c\u1ee7a t\u00e0i li\u1ec7u.<\/p>\n\n\n<pre class=\"wp-block-code\"><code>&lt;head&gt;\n    &lt;link rel=\"preconnect\" href=\"https:\/\/example.com\"&gt;\n&lt;\/head&gt;<\/code><\/pre>\n\n\n<p>K\u1ebft n\u1ed1i tr\u01b0\u1edbc ch\u1ec9 c\u00f3 hi\u1ec7u qu\u1ea3 v\u1edbi c\u00e1c t\u00ean mi\u1ec1n kh\u00e1c v\u1edbi t\u00ean mi\u1ec1n g\u1ed1c c\u1ee7a b\u1ea1n, v\u00ec th\u1ebf b\u1ea1n kh\u00f4ng n\u00ean s\u1eed d\u1ee5ng n\u00f3 cho ch\u00ednh t\u00ean mi\u1ec1n c\u1ee7a b\u1ea1n (v\u00ed d\u1ee5 trang web c\u1ee7a t\u00f4i l\u00e0 kiencang.net, t\u00f4i kh\u00f4ng c\u1ea7n preconnect \u0111\u1ebfn kiencang.net n\u1eefa).<\/p>\n\n\n<p><strong>L\u01b0u \u00fd<\/strong>: Ch\u1ec9 preconnect t\u1edbi c\u00e1c t\u00ean mi\u1ec1n quan tr\u1ecdng m\u00e0 b\u1ea1n s\u1ebd s\u1eed d\u1ee5ng s\u1edbm, b\u1edfi v\u00ec tr\u00ecnh duy\u1ec7t s\u1ebd \u0111\u00f3ng b\u1ea5t k\u1ef3 k\u1ebft n\u1ed1i n\u00e0o kh\u00f4ng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong v\u00f2ng 10 gi\u00e2y. C\u00e1c k\u1ebft n\u1ed1i tr\u01b0\u1edbc kh\u00f4ng c\u1ea7n thi\u1ebft c\u00f3 th\u1ec3 l\u00e0m tr\u00ec ho\u00e3n c\u00e1c t\u00e0i nguy\u00ean quan tr\u1ecdng kh\u00e1c, v\u00ec th\u1ebf gi\u1edbi h\u1ea1n s\u1ed1 l\u01b0\u1ee3ng t\u00ean mi\u1ec1n \u0111\u01b0\u1ee3c k\u1ebft n\u1ed1i tr\u01b0\u1edbc v\u00e0 n\u00ean <a href=\"https:\/\/kiencang.net\/trai-nghiem-link-preconnect\/\" target=\"_blank\" rel=\"noreferrer noopener\">ki\u1ec3m tra \u1ea3nh h\u01b0\u1edfng m\u00e0 preconnect t\u1ea1o ra<\/a>.<\/p>\n\n\n<p>B\u1ea1n c\u0169ng c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng preconnect th\u00f4ng qua <a href=\"https:\/\/developer.mozilla.org\/en-US\/docs\/Web\/HTTP\/Headers\/Link\" target=\"_blank\" rel=\"noreferrer noopener\">Link HTTP header<\/a>:<\/p>\n\n\n<pre class=\"wp-block-code\"><code>Link: &lt;https:\/\/example.com\/&gt;; rel=preconnect<\/code><\/pre>\n\n\n<p>L\u1ee3i \u00edch c\u1ee7a vi\u1ec7c ch\u1ec9 \u0111\u1ecbnh g\u1ee3i \u00fd preconnect trong HTTP header l\u00e0 n\u00f3 kh\u00f4ng ph\u1ea3i d\u1ef1a tr\u00ean c\u00e1c m\u00e3 \u0111\u00e1nh d\u1ea5u \u0111\u00e3 \u0111\u01b0\u1ee3c ph\u00e2n t\u00edch c\u00fa ph\u00e1p, v\u00e0 n\u00f3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c k\u00edch ho\u1ea1t b\u1edfi c\u00e1c y\u00eau c\u1ea7u cho stylesheets, scripts, v\u00e0 nhi\u1ec1u c\u00e1i kh\u00e1c. L\u1ea5y v\u00ed d\u1ee5, Google Fonts g\u1eedi m\u1ed9t Link header trong ph\u1ea3n h\u1ed3i stylesheets \u0111\u1ec3 k\u1ebft n\u1ed1i s\u1edbm (preconnect) v\u1edbi t\u00ean mi\u1ec1n host c\u00e1c file font.<\/p>\n\n\n<p>M\u1ed9t s\u1ed1 ki\u1ec3u t\u00e0i nguy\u00ean, ch\u1eb3ng h\u1ea1n nh\u01b0 font \u0111\u01b0\u1ee3c t\u1ea3i trong ch\u1ebf \u0111\u1ed9 v\u00f4 danh (anonymous mode). V\u1edbi nh\u1eefng t\u00e0i nguy\u00ean nh\u01b0 v\u1eady b\u1ea1n ph\u1ea3i thi\u1ebft l\u1eadp thu\u1ed9c t\u00ednh <em>crossorigin<\/em> v\u1edbi g\u1ee3i \u00fd preconnect:<\/p>\n\n\n<pre class=\"wp-block-code\"><code>&lt;link rel=\"preconnect\" href=\"https:\/\/example.com\/ComicSans\" crossorigin&gt;<\/code><\/pre>\n\n\n<p>N\u1ebfu b\u1ea1n b\u1ecf qua thu\u1ed9c t\u00ednh crossorigin, tr\u00ecnh duy\u1ec7t s\u1ebd ch\u1ec9 th\u1ef1c hi\u1ec7n t\u00ecm ki\u1ebfm DNS m\u00e0 th\u00f4i.<\/p>\n\n\n<hr class=\"wp-block-separator\"\/>\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Phan_giai_ten_mien_som_voi_reldns-prefetch\"><\/span>Ph\u00e2n gi\u1ea3i t\u00ean mi\u1ec1n s\u1edbm v\u1edbi rel=dns-prefetch<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n<p>B\u1ea1n nh\u1edb t\u00ean mi\u1ec1n th\u00f4ng qua t\u00ean c\u1ee7a ch\u00fang, nh\u01b0ng m\u00e1y ch\u1ee7 nh\u1edb ch\u00fang th\u00f4ng qua \u0111\u1ecba ch\u1ec9 IP. \u0110i\u1ec1u n\u00e0y gi\u1ea3i th\u00edch t\u1ea1i sao h\u1ec7 th\u00f4ng ph\u00e2n gi\u1ea3i t\u00ean mi\u1ec1n DNS l\u1ea1i t\u1ed3n t\u1ea1i. Tr\u00ecnh duy\u1ec7t s\u1eed d\u1ee5ng DNS \u0111\u1ec3 chuy\u1ec3n t\u00ean mi\u1ec1n th\u00e0nh \u0111\u1ecba ch\u1ec9 IP. Qu\u00e1 tr\u00ecnh n\u00e0y- t\u1ee9c ph\u00e2n gi\u1ea3i t\u00ean mi\u1ec1n- l\u00e0 b\u01b0\u1edbc \u0111\u1ea7u ti\u00ean \u0111\u1ec3 th\u00e0nh l\u1eadp m\u1ed9t k\u1ebft n\u1ed1i.<\/p>\n\n\n<p>N\u1ebfu trang c\u1ea7n t\u1ea1o k\u1ebft n\u1ed1i t\u1edbi nhi\u1ec1u t\u00ean mi\u1ec1n c\u1ee7a b\u00ean th\u1ee9 ba, k\u1ebft n\u1ed1i tr\u01b0\u1edbc v\u1edbi t\u1ea5t c\u1ea3 ch\u00fang s\u1ebd <em>ph\u1ea3n t\u00e1c d\u1ee5ng<\/em>. G\u1ee3i \u00fd preconnect \u00e1p d\u1ee5ng t\u1ed1t nh\u1ea5t ch\u1ec9 cho c\u00e1c k\u1ebft n\u1ed1i quan tr\u1ecdng nh\u1ea5t. V\u1edbi ph\u1ea7n c\u00f2n l\u1ea1i, b\u1ea1n h\u00e3y s\u1eed d\u1ee5ng <em>&lt;link rel=dns-prefetch&gt;<\/em> \u0111\u1ec3 ti\u1ebft ki\u1ec7m th\u1eddi gian trong b\u01b0\u1edbc \u0111\u1ea7u ti\u00ean- t\u00ecm ki\u1ebfm DNS, c\u00e1i th\u01b0\u1eddng m\u1ea5t t\u1eeb 20-120ms.<\/p>\n\n\n<p>Ph\u00e2n gi\u1ea3i tr\u01b0\u1edbc DNS b\u1eaft \u0111\u1ea7u t\u01b0\u01a1ng t\u1ef1 nh\u01b0 preconnect: b\u1eb1ng c\u00e1ch th\u00eam th\u1ebb <em>&lt;link&gt;<\/em> v\u00e0o ph\u1ea7n <em>&lt;head&gt;<\/em> c\u1ee7a t\u00e0i li\u1ec7u.<\/p>\n\n\n<pre class=\"wp-block-code\"><code>&lt;link rel=\"dns-prefetch\" href=\"http:\/\/example.com\"&gt;<\/code><\/pre>\n\n\n<p><a href=\"https:\/\/caniuse.com\/#search=dns-prefetch\" target=\"_blank\" rel=\"noreferrer noopener\">Tr\u00ecnh duy\u1ec7t h\u1ed7 tr\u1ee3 cho dns-prefetch<\/a> h\u01a1i kh\u00e1c so v\u1edbi c\u00e1c <a href=\"https:\/\/caniuse.com\/#search=preconnect\" target=\"_blank\" rel=\"noreferrer noopener\">h\u1ed7 tr\u1ee3 d\u00e0nh cho preconnect<\/a>, v\u00ec th\u1ebf dns-prefetch c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c d\u00f9ng nh\u01b0 d\u1ef1 ph\u00f2ng (fallback) cho c\u00e1c tr\u00ecnh duy\u1ec7t kh\u00f4ng h\u1ed7 tr\u1ee3 preconnect.<\/p>\n\n\n<p>H\u00e3y l\u00e0m nh\u01b0 sau:<\/p>\n\n\n<pre class=\"wp-block-code\"><code>&lt;link rel=\"preconnect\" href=\"http:\/\/example.com\"&gt;\n&lt;link rel=\"dns-prefetch\" href=\"http:\/\/example.com\"&gt;<\/code><\/pre>\n\n\n<p>\u0110\u1ec3 tri\u1ec3n khai k\u1ef9 thu\u1eadt d\u1ef1 ph\u00f2ng, b\u1ea1n h\u00e3y s\u1eed d\u1ee5ng c\u00e1c th\u1ebb link ri\u00eang bi\u1ec7t.<\/p>\n\n\n<p>Kh\u00f4ng n\u00ean l\u00e0m nh\u01b0 d\u01b0\u1edbi \u0111\u00e2y:<\/p>\n\n\n<pre class=\"wp-block-code\"><code>&lt;link rel=\"preconnect dns-prefetch\" href=\"http:\/\/example.com\"&gt;<\/code><\/pre>\n\n\n<p>Tri\u1ec3n khai d\u1ef1 ph\u00f2ng dns-prefetch n\u1eb1m c\u00f9ng th\u1ebb &lt;link&gt; g\u00e2y ra l\u1ed7i trong tr\u00ecnh duy\u1ec7t Safari khi m\u00e0 preconnect s\u1ebd b\u1ecb b\u1ecf qua.<\/p>\n\n\n<hr class=\"wp-block-separator\"\/>\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Ket_luan\"><\/span>K\u1ebft lu\u1eadn<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n<p>Hai ki\u1ec3u g\u1ee3i \u00fd t\u00e0i nguy\u00ean tr\u00ean h\u1eefu \u00edch trong vi\u1ec7c c\u1ea3i thi\u1ec7n t\u1ed1c \u0111\u1ed9 trang khi b\u1ea1n bi\u1ebft b\u1ea1n s\u1ebd t\u1ea3i c\u00e1i g\u00ec \u0111\u00f3 s\u1edbm t\u1eeb t\u00ean mi\u1ec1n c\u1ee7a b\u00ean th\u1ee9 ba, nh\u01b0ng b\u1ea1n l\u1ea1i kh\u00f4ng bi\u1ebft ch\u00ednh x\u00e1c URL c\u1ee7a t\u00e0i nguy\u00ean. V\u00ed d\u1ee5 g\u1ed3m CDN ph\u00e2n ph\u1ed1i c\u00e1c th\u01b0 vi\u1ec7n JavaScript, c\u00e1c \u1ea3nh ho\u1eb7c font. H\u00e3y ch\u00fa \u00fd \u0111\u1ebfn nh\u1eefng h\u1ea1n ch\u1ebf, s\u1eed d\u1ee5ng preconnect ch\u1ec9 cho c\u00e1c t\u00e0i nguy\u00ean quan tr\u1ecdng nh\u1ea5t, d\u1ef1a v\u00e0o dns-fetch cho ph\u1ea7n c\u00f2n l\u1ea1i, v\u00e0 lu\u00f4n lu\u00f4n <a href=\"https:\/\/kiencang.net\/chi-so-hieu-suat-nguoi-dung\/\" target=\"_blank\" rel=\"noreferrer noopener\">\u0111o \u0111\u1ea1c \u1ea3nh h\u01b0\u1edfng trong th\u1ebf gi\u1edbi th\u1ef1c (real-world)<\/a>.<\/p>\n\n\n<p><em>(D\u1ecbch t\u1eeb b\u00e0i vi\u1ebft: Establish network connections early to improve perceived page speed, t\u00e1c gi\u1ea3: Milica Mihajlija, trang web[.]dev)<\/em><\/p>\n\n\n<hr class=\"wp-block-separator\"\/>\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Bonus_cho_nguoi_dung_WordPress\"><\/span>Bonus cho ng\u01b0\u1eddi d\u00f9ng WordPress<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n<p>\u0110\u1ec3 s\u1eed d\u1ee5ng preconnect hi\u1ec7u qu\u1ea3 tr\u00ean WordPress b\u1ea1n c\u1ea7n 2 th\u1ee9:<\/p>\n\n\n<ul><li>Bi\u1ebft r\u00f5 trang c\u1ea7n t\u00e0i nguy\u00ean c\u1ee7a b\u00ean th\u1ee9 ba n\u00e0o. C\u00f3 hai c\u00f4ng c\u1ee5 m\u00e0 b\u1ea1n n\u00ean k\u1ebft h\u1ee3p, \u0111\u00f3 l\u00e0 tab Network trong c\u00f4ng c\u1ee5 d\u00e0nh cho nh\u00e0 ph\u00e1t tri\u1ec3n c\u1ee7a Chrome  (hi\u1ec3n th\u1ecb chi ti\u1ebft qu\u00e1 tr\u00ecnh t\u1ea3i), v\u00e0 <a href=\"https:\/\/tools.pingdom.com\/\" target=\"_blank\" rel=\"noreferrer noopener\">Tool Pingdom<\/a> (r\u1ea5t tr\u1ef1c quan).<\/li><li>S\u1eed d\u1ee5ng plugin \u0111\u1ec3 preconnect c\u00e1c t\u00e0i nguy\u00ean t\u01b0\u01a1ng \u1ee9ng tr\u00ean trang c\u1ee5 th\u1ec3, v\u00ec th\u01b0\u1eddng th\u00ec kh\u00f4ng ph\u1ea3i trang n\u00e0o c\u0169ng c\u1ea7n preconnect \u0111\u1ebfn c\u00f9ng m\u1ed9t t\u00e0i nguy\u00ean, v\u00ed d\u1ee5 nh\u01b0 c\u00f3 trang nh\u00fang video YouTube, c\u00f3 trang kh\u00f4ng, do v\u1eady vi\u1ec7c <a href=\"https:\/\/kiencang.net\/preconnect-youtube\/\" target=\"_blank\" rel=\"noreferrer noopener\">preconnect \u0111\u1ebfn c\u00e1c t\u00e0i nguy\u00ean t\u01b0\u01a1ng \u1ee9ng c\u1ee7a YouTube<\/a> ph\u1ee5 thu\u1ed9c v\u00e0o trang c\u1ee5 th\u1ec3 c\u00f3 nh\u00fang video hay kh\u00f4ng. <\/li><\/ul>\n\n\n<p>Plugin m\u00e0 b\u1ea1n c\u1ea7n l\u00e0: <a href=\"https:\/\/vi.wordpress.org\/plugins\/oh-add-script-header-footer\/\" target=\"_blank\" rel=\"noreferrer noopener\">SOGO Add Script to Individual Pages Header Footer<\/a> &#8211; n\u00f3 hay l\u00e0 v\u00ec b\u1ea1n c\u00f3 th\u1ec3 th\u00eam v\u00e0o khu v\u1ef1c <em>&lt;header&gt;<\/em> cho c\u1ee5 th\u1ec3 t\u1eebng trang m\u00e0 b\u1ea1n mu\u1ed1n (c\u00e1c c\u00f4ng c\u1ee5 th\u00f4ng th\u01b0\u1eddng kh\u00e1c s\u1ebd b\u1ed5 sung v\u00e0o header cho t\u1ea5t c\u1ea3 c\u00e1c trang). Nh\u1edd th\u1ebf m\u00e0 b\u1ea1n t\u00f9y bi\u1ebfn \u0111\u01b0\u1ee3c cho t\u1eebng trang ri\u00eang bi\u1ec7t.<\/p>\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><img decoding=\"async\" src=\"https:\/\/kiencang.net\/wp-content\/uploads\/2020\/03\/them-ma-tuy-chinh.png\" alt=\"th\u00eam m\u00e3 t\u00f9y ch\u1ec9nh link preconnect v\u00e0o trang c\u1ee5 th\u1ec3 tr\u00ean WordPress\" class=\"wp-image-15225\"\/><figcaption>D\u00f2ng cu\u1ed1i b\u1ecb thi\u1ebfu thu\u1ed9c t\u00ednh crossorigin, v\u00ec \u0111\u00e2y l\u00e0 font<\/figcaption><\/figure><\/div>\n\n\n<p>C\u00f4ng c\u1ee5 tuy \u0111\u01a1n gi\u1ea3n nh\u01b0ng r\u1ea5t h\u1eefu \u00edch, n\u00f3 c\u0169ng ho\u1ea1t \u0111\u1ed9ng t\u1ed1t. \u0110i\u1ec3m tr\u1eeb duy nh\u1ea5t l\u00e0 nh\u00e0 ph\u00e1t tri\u1ec3n plugin c\u00f3 v\u1ebb kh\u00e1 c\u1ea9u th\u1ea3 khi vi\u1ebft ph\u1ea7n m\u00f4 t\u1ea3 cho n\u00f3.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Trong b\u00e0i vi\u1ebft n\u00e0y ch\u00fang ta s\u1ebd c\u00f9ng h\u1ecdc c\u00e1ch s\u1eed d\u1ee5ng c\u00e1c ki\u1ec3u g\u1ee3i \u00fd t\u00e0i nguy\u00ean rel=preconnect v\u00e0 rel=dns-prefetch. Tr\u01b0\u1edbc khi tr\u00ecnh duy\u1ec7t c\u00f3 th\u1ec3 y\u00eau c\u1ea7u m\u1ed9t t\u00e0i nguy\u00ean t\u1eeb m\u00e1y ch\u1ee7, n\u00f3 ph\u1ea3i th\u00e0nh l\u1eadp k\u1ebft n\u1ed1i. Th\u00e0nh l\u1eadp m\u1ed9t k\u1ebft n\u1ed1i b\u1ea3o m\u1eadt (secure connection) li\u00ean quan \u0111\u1ebfn ba b\u01b0\u1edbc: &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[291],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v21.6 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Th\u00e0nh l\u1eadp c\u00e1c k\u1ebft n\u1ed1i m\u1ea1ng s\u1edbm (preconnect) \u0111\u1ec3 c\u1ea3i thi\u1ec7n t\u1ed1c \u0111\u1ed9 website &#8226; Ki\u1ebfn c\u00e0ng<\/title>\n<meta name=\"description\" content=\"Preconnect l\u00e0 m\u1ed9t trong c\u00e1c gi\u1ea3i ph\u00e1p \u0111\u01a1n gi\u1ea3n, hi\u1ec7u qu\u1ea3 \u0111\u1ec3 c\u1ea3i thi\u1ec7n t\u1ed1c \u0111\u1ed9 website, \u0111\u1eb7c bi\u1ec7t trong b\u1ed1i c\u1ea3nh c\u00e1c website hi\u1ec7n \u0111\u1ea1i s\u1eed d\u00f9ng nhi\u1ec1u t\u00e0i nguy\u00ean c\u1ee7a b\u00ean th\u1ee9 ba.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/kiencang.net\/preconnect-dns-prefetch\/\" \/>\n<meta property=\"og:locale\" content=\"vi_VN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Th\u00e0nh l\u1eadp c\u00e1c k\u1ebft n\u1ed1i m\u1ea1ng s\u1edbm (preconnect) \u0111\u1ec3 c\u1ea3i thi\u1ec7n t\u1ed1c \u0111\u1ed9 website &#8226; Ki\u1ebfn c\u00e0ng\" \/>\n<meta property=\"og:description\" content=\"Preconnect l\u00e0 m\u1ed9t trong c\u00e1c gi\u1ea3i ph\u00e1p \u0111\u01a1n gi\u1ea3n, hi\u1ec7u qu\u1ea3 \u0111\u1ec3 c\u1ea3i thi\u1ec7n t\u1ed1c \u0111\u1ed9 website, \u0111\u1eb7c bi\u1ec7t trong b\u1ed1i c\u1ea3nh c\u00e1c website hi\u1ec7n \u0111\u1ea1i s\u1eed d\u00f9ng nhi\u1ec1u t\u00e0i nguy\u00ean c\u1ee7a b\u00ean th\u1ee9 ba.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/kiencang.net\/preconnect-dns-prefetch\/\" \/>\n<meta property=\"og:site_name\" content=\"Ki\u1ebfn c\u00e0ng\" \/>\n<meta property=\"article:author\" content=\"https:\/\/www.facebook.com\/anhducnguyen87\/\" \/>\n<meta property=\"article:published_time\" content=\"2020-03-12T03:57:31+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/kiencang.net\/wp-content\/uploads\/2020\/03\/preconnect-1024x690-3.png\" \/>\n<meta name=\"author\" content=\"Nguy\u1ec5n \u0110\u1ee9c Anh\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u0110\u01b0\u1ee3c vi\u1ebft b\u1edfi\" \/>\n\t<meta name=\"twitter:data1\" content=\"Nguy\u1ec5n \u0110\u1ee9c Anh\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u01af\u1edbc t\u00ednh th\u1eddi gian \u0111\u1ecdc\" \/>\n\t<meta name=\"twitter:data2\" content=\"9 ph\u00fat\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Th\u00e0nh l\u1eadp c\u00e1c k\u1ebft n\u1ed1i m\u1ea1ng s\u1edbm (preconnect) \u0111\u1ec3 c\u1ea3i thi\u1ec7n t\u1ed1c \u0111\u1ed9 website &#8226; 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